Former FBI Director James Comey has some unsolicited and apparently unwanted advice for President Trump’s lawyers: Think hard before you let your client be interviewed by Special Counsel Robert Mueller and his investigators because your “client is somebody who lies a lot.”

“That doesn’t mean you don’t do it, and I actually believe as an American it’s very important that a president cooperate,” Comey said in an interview today about the impact of his bestselling book, “A Higher Loyalty:Truth, Lies, and Leadership,”, during a Washington Post Live Event with reporter Carol D. Leonnig.

“But you’d have to, as a lawyer, be very thoughtful and prepare your client,” added Comey.

Comey’s comments come at a time Trump is considering whether to grant an in-person interview that Mueller has requested, with his lawyers wary of allowing the president to do so.

Among those against an interview is a recent addition to Trump’s legal team, Rudy Giuliani, the former New York City Mayor and U.S. Attorney in New York.

One reason Giuliani has cited is his concern that Mueller will take Comey’s word over Trump’s version of events.

On Sunday on ABC’s “This Week,” Giuliani said, “People lie. Could Comey be lying? You’re damn right he could be lying. … And we’re going to walk ourselves into a trap like that?”

Giuliani told ABC’s George Stephenoupolous that Mueller must convince Trump and his legal team that he would be open to believing Trump.

“The special counsel so far seems to think that Comey is Moses,” said Giuliani. “And I happen to think Comey is Judas.”

Comey declined in his interview today to say specifically if he would recommend Trump talk to Mueller if he was one of the president’s attornies, but he did say that they would have to carefully prepare their client and make sure he understands one important thing.

“This is one,” said Comey, “you cannot BS your way through.”

In his book, Comey said as a young prosecutor who played a central role in taking down the New York area organized crime group known as the mafia, he greatly admired Giulini, his then-boss, but he feels he has “changed over time.”

Comey joked to the Washington Post: “I guess the love is gone. I used to be one of his star prosecutors. It appears I’m not anymore.”

Comey also came to the defense last week of the U.S. Attorney’s prosecutors and the FBI agents where he and Giuliani once worked together.

Giuliani last week referred to the agents who raided the office, home and hotel room of Trump’s personal lawyer Michael Cohen as “stormtroopers,” using a term coined to describe specially trained German soldiers in World War I and later adopted by vicious Nazi paramilitary units.

I know the New York FBI. There are no “stormtroopers” there; just a group of people devoted to the rule of law and the truth. Our country would be better off if our leaders tried to be like them, rather than comparing them to Nazis.

While Giuliani appears to be out of control, making claims on behalf of the president that even the president says are not true, Comey has continued to conduct himself with dignity and class even as he has weathered a series of vicious attacks by Trump and the right wing.

So Comey is giving Trump and Giuliani good advice: Don’t let the president give an on the record interview to Mueller, because inevitably he will lie and get caught.

Trump and Giuliani should thank Comey for his advice, not condemn him, but instead, they will almost certainly ust continue to lie about him.